This invention relates to a tape recorder having an electronic counter circuit used for end of tape detection, and an alarm generation means.
Tape recorders are usually provided with a tape counter for indicating the amount of running of a tape. Hitherto, a mechanical counter which has number gears rotated in an interlocked relation to the rotation of a reel shaft and displays the amount of running of the tape with a corresponding number has been used. Recently, an electronic counter circuit which comprises a pulse generator for producing a pulse signal in accordance with the rotation of a reel shaft to count these pulses so that the count thereof indicates the amount of running of the tape is in use. The electronic counter circuit can effect various controls with its count value. For example, it can automatically stop the running of the tape when the tape is run up to a predetermined count value at the time of the fast forward or rewind operation. It can also automatically stop the running of the tape when the tape is completely wound on one of the reels, that is, when a tape end state is brought about. In the electronic counter circuit, a high power is consumed in a display section, so that it is desirable to disconnect the electronic counter circuit from the power source when the running of the tape is stopped. However, even at the time of switching of operation modes, for instance from a playback mode over to a rewind mode, the running of the tape is temporarily stopped. At this time, the counter is reset, and the display on the display section disappears. Therefore, the count value corresponds to the amount of running of the tape from a position thereof assumed each time when the running of the tape is stopped. In other words, once the running of the tape is stopped, a value corresponding to the amount of running of the tape from the initial position thereof, i.e., the tape position when the tape is entirely wound on one of the reels, can no longer be obtained. This means that such a control as stopping the running of the tape at a desired count value is interfered with. Accordingly, it is in practice to control the power supply to the display section by providing a switch for the display section separately from the operation switches for the tape recorder. In this case, however, the mechanism is complicated, and also it is likely that the display disappears with erroneous operation of the switch.
It is usually adopted in tape recorders that when the tape is run to the end, the power source for the tape recorder is automatically disconnected to stop the running of the tape. At this time, it is desired to provide an alarm of some sort. In the playback, when the power source is automatically disconnected, the playback sound ceases so that the operator can recognize the tape end state. In the recording mode, however, the operator has to perceive the tape end state by sight unless the recording signal is monitored or an alarm is given at the time when the tape end state is brought about. In this case, if the recording mode is continued without noticing the tape end state, the subsequent recording fails, or in order not to miss the occurrence of the tape end state, extra attention has to be paid.